1. Field of the Invention
The present invention relates to a reversed terminal insertion preventing structure which can detect reversed insertion from contacts between a projection of a terminal with a part of a connector housing when the terminal is inserted into the connector housing upside down.
2. Description of the Related Art
FIGS. 7 and 8 show a conventional reversed terminal insertion preventing structure which is disclosed in Japanese Utility Model Application Laid-Open No. 61-80576.
This structure prevents a terminal 52 from being inserted into a synthetic resin connector housing 51 upside down. A semi-circular protrusion 53 is provided on the back of the terminal 52. A guide groove 55 is formed to accommodate the protrusion 53 at the bottom of the terminal receiving chamber 54 in the connector housing 51. As shown in FIG. 7, when the terminal 52 is inserted correctly, the protrusion 53 is situated at the end of the guide groove 55.
A notch 56 is formed on the top wall 58 of the terminal receiving chamber 54 in the connector housing 51. A contact surface 57 is formed to block the protrusion 53 at the front side of the notch 56 at the mid-point on the top wall 58 in the terminal insertion direction. As shown in FIG. 8, when the terminal 52 is inserted upside down, the protrusion 53 is blocked by the contact surface 57 so as to prevent the insertion of the terminal 52 halfway. Thus, the reversed insertion of the terminal 52 can be detected.
With the conventional preventing structure, however, there is a problem that the height H (shown in FIG. 7) of the protrusion 53 cannot be increased due to the limitation of the space in the connector housing 51, and because of this, the contact area between the protrusion 53 and the contact surface 57 is small, resulting in the reversed insertion of the terminal 52. If the contact area is small, it is impossible to obtain a prevention force large enough to prevent the reversed insertion of the terminal 52. There is another problem that whether the terminal 52 is inserted correctly or upside down, the protrusion 53 hits the contact surface 57 of the notch 56 or the end surface of the guide groove 55, putting an unnecessarily large force onto the protrusion 53. Thus, only a part of the terminal 52 is subject to stress, resulting in deformation of the terminal 52.